DE2335014B2 - Rejection process - Google Patents

Description

The invention relates to a method for processing of excreted, because insufficiently frayed oreballs. Splinters and bundles of fibers during defibering and sorting in an aqueous suspension $ ion ve.-lying bevel raw materials such as wood pulp. Hoiz cellulose and cellulose / u Gutsioff for paper ·. Kar lon and cardboard dissection.

The main fiber raw materials for the paper and cardboard production are Flol / Schliff and Wood pulp that has to be suspended in water for later processing. So that these raw materials get the required degree of fineness, successful Careful sorting, with excessively coarse or insufficiently digested parts one or more digestion and sorting stages are carried out. This is the only way to guarantee that a The largest possible amount of the material used for ti ic production is bet that the material is therefore economical is used. Only those components that are still too coarse after these digestion sorting stages and therefore could lead to faulty manufacturing or rejects, are eliminated and go into the sewage.

So that, for example, Hol / Schliff gets the degree of breakdown required for paper production and is free of specks and coarse particles. it is carefully ground and sorted. This digestion takes place in several stages, whereby the so-called rejects are too coarse files. Splitter untl I aseroundei. excreted if yes and thus mate; .alloss means. With regard to the number of digestion or sorting stages, there is an economic optimum, because even with the addition of additional slips, a certain amount of reject material can hardly be undershot. Decisive for the amount of material losses is the level of Fech' · ν for the wet grinding and sorting of fiber suspensions. It amounts to the material losses, which are different in the individual manufacturing plants. / wichen I .. 5 Gewiehisieiien the cmgc.ei / ten & s raw materials These material losses represent a considerable disadvantage in terms of manufacturing technology! development of paper and Ka ^r Tondar

Both the paper and cardboard industries. as well as the Manufacturer of the h.?a. Required for this industry machines have been trying this industry for so long oibi to reduce rejects loss. without doing anything To have found suitable solutions so far

It is the object of the invention. this reject, that is to say the excessively coarse parts of the splinters and fiber bundles that appear after the digestion and sorting of the fiber suspension, also fills out to the extent that they are accepted as accepting of the paper. Pa and carton ₁ may be peherstelluns supplied.

According to the invention, this is achieved in that the reject is first placed on a solid material. thickened by 40% or more, dehydrate in you 1 »Form> n Frockenmuhlen. preferably PralJ / explained runosmühlen. finely ground (frayed), brought back into the state of pension and then added to the wood pulp suspension again
^Γ According to the invention, thus leaving the previously '· -is began recovering path of Nuiirnahlung and a dry mahlschntt in the brightening of the I aserrohstoffs he joined Extensive tests was give in sen and secured that the case be achieved ul \ circuit and The degree of grinding corresponds to that of the Naßniablun.i. The concentration and drying can be carried out so economically that the effort is low · .-: is. as if one were to add a further stage to the wet grinding and sorting systems, with which one cannot achieve the desired success, namely, to work without material loss.

When thickening or drying, it is important to separate as much water as possible mechanically or thermally for reasons of energy expenditure for the subsequent dry grinding. When the degree of dryness is high, the power required for grinding is lowest and the degree of fineness of the accepted material is best. Depending on the energy utilization of the company or the energy price and the desired degree of grinding of the material, the result is an optimum with regard to the drying of the mowing: if the energy costs are negligible and if a further drying stage would make the system disproportionately expensive, more moist material can be ground, as / o solids content is driven in the cases where, for reasons of energy saving, the drying, for example by art "another type of energy, further, for example up to 90".

The in the inventive method for Vcr Devices and machines that are coming to this end are part of technology in the individual cases, but have not yet been used in the combination according to the invention. So becomes more purposeful wise, the rejects coming to the processing are first passed into a collecting box, where they are collected by rain

1 jj._ ϋΐ, .ΓΜί ^ Κι »_jijf /» inen ulpirhhlcMhenden I esl-

material content of about 0.5 to 1.0% is brought.

Then he is on band filters. Centrifuges or similar machines to the desired f esisioffge stop thickened by about 40%. It can also be used on a curved sieve with a solids content of up to about 7% watered and then in a snail pike on 40 to 45% plastic can be thickened. If necessary, the reject thus prepared is still in a dryer for a higher solids content undried!

The method according to the invention is described below using an example:

Zenincleaner SiwckMoff au. the grinding shop

Paper mill is collected in a collection biiiie, in the subject matter / and level are regulated. the The solids concentration / entraion is set to elwa I "·». With the help of a stock pump, about 1100 oi of suspension with an I estsnf (content v <m 1.58% continuously a 320 m wide and IbOD nim long curved sieve, its I ingangsduse on 4 bar pressure is set. At the exit from the Bo The sieve is the solids content aiii) »4 · 'Ί> increased Das Siebdiin.hschiagwas-.er with a Fesistoffkun / entration Min 0.2 "Ί> becomes the Verdumiiiiigsvv j scr the l'j pierfabnkaiion fed

The dehydrated material is fed to a screw press, which ^{thickens it to an oil content of around 40 IJ} .i) and then grinds it. The water separated on the cW screw press is also fed into the dilution water. After drying, the thickened material arrives with the help of a transfer screw in the dissolver of a float drying system, which hurls it into the hot air swirl chamber of the dryer. The product particles dried to the desired solids consistency / of about bCH t are discharged from the dryer by the air stream and separated in a cyclone. The dry product is discharged through a discharge lock: the air ... Heating chamber and thus fed to the drying process. This linear running system prevents self-ignition of the frock product in a manner known per se.

After drying, around 5520 kg of pulp are found Ciramilat with a solids content of about b () "/ o. that continuously from the dryer to the next one Pralitetier-I eiumahlmuhSe is supplied. Here will iias grist from a rapidly rotating centrifugal egg rad cri.iHi and against the grinding segments the pralhetlir kai.imer thrown. The crushed particles ent give way through an annular gap / wipe housing and centrifugal wheel in a (iehäusekammer. wo they are converted back into a fiber suspension by spraying water to be led back. This fiber suspension can now be used as the pulp for paper production are fed.

The dry grinding possible through the thickening or drying of the rejects gives a digestion and degree of grinding that corresponds to the Α11Γ-final degree of the wood pulp in the wet grinding / ur production of paper. Those who have been eliminated so far (All parts from the wood / grinding process are thus returned to the paper manufacturing process as material.

Claims (2)

Patent claims: 1. Process / for processing excreted, as insufficiently frayed fibers. Spliters and fiber bundles of those present in the defibering and sorting of in an aqueous suspension Fiber raw materials, such as hol / grinding. Fetch / pulp and / rush «»: to C.iits.off to paper-cardboard and cardboard production, thereby marked ic draws. then the excreted substances first thickened to a solids content of 40'-Vn or more, in this dehydrated form in rrockenmuhlen. preferably JVall grinding mills. finely ground, brought back into suspension and then again the aqueous wood suspension be added. 2 Apparatus for carrying out the method according to claim 1, characterized in that the dry mill is a PrallteUermuhle mn a water injection device acting on the ground Ciut